Southwest Airlines on Tuesday flew into uncharted territory for the company, with its first-ever international flight, according to a story from USA Today.

The low-cost airline's first international departure was Southwest Flight 1804, which was scheduled to leave Baltimore/Washington International Airport for Aruba at 8:30 a.m. on Tuesday, USA Today reported.

That flight is one of six scheduled internationally on Tuesday for Southwest. The other routes are: Baltimore-Montego Bay, Jamaica; Atlanta-Aruba; Atlanta-Montego Bay; Baltimore-Nassau, Bahamas; and Orlando-Montego Bay, according to the Los Angeles Times.

Southwest is taking over the routes from its subsidiary airline, AirTran Airways, the LA Times reported.

For now, the Southwest flights only will be to the Caribbean, but the airline has plans to add other destinations, according to news reports. Southwest will add Cancun and Los Cabos, Mexico on Aug. 10, and will add Mexico City and Punta Canas, Dominican Republic on Nov. 2, the LA Times reported.

"This opens up all of North America to us," Southwest CEO Gary Kelly told USA Today. "We've pinpointed 50 potential destinations that could be several hundred aircraft worth of growth. It opens up Hawaii, Alaska, Canada, the Caribbean, Central America and even the northern tier of South America."

USA Today reported that Southwest's expansion plans will rely on the range of the Boeing 737, which is the only type of aircraft that the airline flies.

When Southwest expands international service in August, Milwaukee and Orange County, California will be added to the soon-to-be growing list of Southwest airports that offer international service, according to USA Today. In November, Southwest will add Austin, Chicago's Midway airport and San Antonio to that list.

Within the next year or two, the airline plans to add international flights to its base airports at Houston's Hobby airport and in Fort Lauderdale, Florida, USA Today reported.

"[B]eyond that, we'll keep those as closely guarded secrets as where we want to focus," Kelly told USA Today, talking about future airports. "It could take us another 25 years to add 50 cities."